Plumb display state and interactive information to BatteryStats.

Fixes an issue where dozing was treated the same as the screen
being fully on.  Now dozing is treated the same as the screen
being fully off which is slightly better.  The decision of how
to represent this state is now internal to the battery stats
so it can be improved later.

Removed noteInputEvent() since it is unused.

Bug: 14480844
Change-Id: Iee8cf8dce1a1f91c62678bb6d3d9fe567ad6db42